Operating mechanism



- Oct. 19, 1937. o. c. PRINCE OPERATING MECHANISM Filed Oct. 19. 19:4

Fig.2.

D lrjvgrlw torz avid wince, 10 5 W isAttorne Patented Oct. 19, 1937 PATENT OFFICE OPERATING MECHANISM David 0. Prince, Swarthmore, Pa., assignor to General Electric Company, a corporation of New York Application October 19, 1934, Serial No. 749,056

4Claims.

My invention relates to operating mechanisms, more particularly to mechanisms employing an explosive charge as the actuating means, and has for its principal object the provision of an 6 improved operating mechanism of the aforesaid type which shall be positive and eflicient in operation and simple, compact and inexpensive in construction.

Certain operations, as closing of a. large electric circuit breaker for example, require the application of considerable force thoughout a short distance and over a very short period of time. Heretofore the closing mechanisms of oil circuit breakers, such as solenoids, motor mechanisms,

18 etc. have assumed a considerable part of the breaker cost as compared with the amount of time that the mechanisms are in use. A simple and inexpensive operating mechanism which is capable of efficiently applying adequate closing force is, therefore, highly desirable.

In accordance with my invention, the size and cost of the operating mechanism are appreciably reduced by using an explosive charge as a slow burning powder, for the actuating means. The

mechanism is adapted for a plurality of automatic operations by means of a firing device which is automatically reset in response to operation of said mechanism.

My invention will be more fully set forth in so the following description referring to the ac companying drawing, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

Referring to the drawing, Fig. 1 is a view, partly diagrammatic and partly in section, of an operating mechanism embodying my invention and Fig. 2 illustrates the application of the aforesaid mechanism to an electric circuit breaker.

The operating mechanism illustrated by Fig. 1 may be of general application where a limited number of operations are desired without servicing of the mechanism. The mechanism comprises a suitable pressure resisting casing I and a plunger or piston 2 which is mounted and guided in the upper wall of the casing for reciprocal movement. The casing I has mounted therein a cartridge receiving block 3 for retaining a plurality of cartridges 4. A detachable cap 5 normally closes the lower end of the casing.

The cartridge 4 may be of any suitable form and in the present instance comprises a casing 6 containing an explosive charge I, as a suitable slow burning powder. The explosive charge I is ignited electrically, as by a fusible or heating element 8 energized in a manner hereinafter described. The cartridge 4, which is inserted within a bore 9 from the lower side of the block 3, may be removed after discharge and replaced by another cartridge through the lower end of the casing by reason of the detachable cover 5.

A plurality of cartridges 4 are mounted within the block 3 and are individually fired by means of a separate firing device III which is operatively connected to the piston 2 so as to place a. fresh cartridge in readiness for a subsequent operation. The firing circuit for each cartridge includes a source of potential as a battery II which is connected at one terminal through a conductor I2 to the metallic casing I, and at the other terminal 15 through a control switch I3 and firing device III to the cartridge. I

Closing of a particular cartridge circuit causes current to fiow from the battery II through switch I3, firing device In, and cartridge heating 20 element 8 which is electrically connected to the metallic casing I through the metallic cartridge casing 6 and block 3, to cause firing of the cartridge and upward movement of the actuating piston 2. 2

Referring more particularly to the electrical connections, the firing device I0 comprises a switch arm l4 which is mounted on a, rotatable shaft I5 for coacting with a plurality of radially disposed contacts I6. Connected to the shaft I5 30 is a ratchet wheel I! which is operatively connected to the piston 2 through a lever I8 and pawl I9, the arrangement being such that each descending or return stroke of the piston 2 causes counter-clockwise rotation of the ratchet wheel I'I one notch so as to move the switch arm I4 out of engagement with one contact I6 and into engagement with the next contact.

The pawl lever I8 is pivotally connected at one end to a sleeve 20 secured to the piston 2 and at its other end to the pawl IS, an extension 2| of the casing I providing a lost motion pivotal mounting at 22. The pawl I9 is maintained in operative position with respect to the wheel IT, as by a tension spring 24 tending to bias the pawl 45 in clockwise direction. Acordingly, after a working and return stroke of the piston 2 the pawl I9 is in readiness, as illustrated, for a subsequent actuation of the firing device Ill.

The control switch I3 comprises a simple snap switch having an over center spring 25 and a pivoted switch arm 26 adapted to make momentary contact at 21. The contact 21 is electrically connected to the switch arm I4 as by contact 28 engaging a conducting collar 29 which is elec- 5.

' ,ing stroke. 'Accordingly, the operating piston 2- is acted on by a comparatively-large andpositive force throughout its short stroke.

trically connected to the switch arm l4 and insulated with respect to the shaft 15. Each contact I 5 is separately connected to a" corresponding terminal 30 mounted in the bottom of detachable cap 5. Each terminal 30 comprises a conducting member as a pin 3| extending through and-insulated with respect to the cap 5, as at 32, and

' adapted to make'electrical contact with the corresponding cartridge terminal 33. The cartridge The momentary contact establishes a circuit as a slot 2', for permitting exhaust of the gases and products of combustion from the casing I through the firing device l0 and one of the cartridges within thecasing, resulting in ignition of the powder charge, generation of pressure within the casing and projection oi the'piston Zupwardly. The piston 2 is suitably provided with means,

whenthe piston is at or near the end of its work- As previously described,,a working stroke of the piston 2' moves the pawl I9' beneaththe' next,

ratchet tooth so that the return stroke rotates the ratchet wheel l1 one notch in a counter-'clockwise direction to move the'switch, arm. I 4 into contact with the next contact i5. With this arrangement a cartridge cannot be fired by thecontrol switch unless the piston 2 is in the'proper position to deliver a working stroke.

Operation of control switch l3 again fires thecartridge associated with the newlyestablished circuit, the above described cycle being repeated until the switch arm M has made a revolution.

expensive revolver devices for the cartridges are avoided. Furthermore, the control switch l3 lends the mechanism to remote control operation.

Fig. 2 illustrates the application of my improved operating mechanism to a large capacity oil circuit breaker. The circuit breaker generally indicated at 40 comprises stationary contact structure 4| mounted at the lower ends 01' lead-in bushings 42 and a movable conducting bridging member 43. The contact structure is normally oil immersed within a casing (not shown). The breaker is illustrated in the open circuit position, closing of the circuit being efiected by raising of the bridging member 43 by the operating or lift-rod 44 so as to engage and interconnect the stationary contacts 4|.

The circuit breaker lift-rod 44 is operatively connected to the piston 2 of the operating mechanism through suitable force-transmitting linkage. In the present instance a bellcrank 45 pivotally mounted at 45 is actuated by the piston 2 in counter-clockwise direction to cause closing of the breaker. One arm of the bellcrank 45 is consponseto excess current.

nected at 41 through a linkage 48 to an operating lever 45. Thelever 49 is connected at 5D to a linkage 5|. for 'causing'substantialiy reciprocal movement of the rod 44 in response to rotation of the lever 45; The other arm of the bellcrank 45 is connected at 52 to a collapsible restraining linkage 53 which coacts with a tripping solenoid 54. The solenoid 54 may be associated with the usual current transformer 55 so that the tripping linkage 53 is tripped by the solenoid 24' in re- Tripping or collapse of the linkage 53, as will be apparent, permits the bellcrank 45 to rotate clockwise to the open circuit position shown.

. Closing of the circuit breaker by the operating mechanism is eflected by the-aforesaid firing operation and upward movement of the piston 2 l which engages a roller 55 carried by the bellcrank 45. The resulting counter-clockwise rotation of the bellcrank 45 transmits clockwise movement nism only when the circuit breaker is in open circuit position, an auxiliary'switch 45' operatively connected to the bellcrank 45 is included in the circuit I2. This switch is closedonly when the circuit breaker is open.

- It will be apparent that the amount and character, of the explosive charge may be chosen to suit the particular operating requirements of the mechanism. For example, slow burning powderswhich are well known in the art may produce a positive and eifective closing operation compar able tothat produced by strong compremion springs and solenoids without excessive shock or impact. The operating characteristics of I the mechanism are furthermore particularly suited to closing of large circuit breakers, as compared with solenoids, since the circuit breaker mechanism resistance is comparatively large at and near the end of the closing stroke. An operating mechanism as above described therefore operates very efilciently under such conditions since a large operating force is available throughout the working stroke.

It should be understood that my invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. Operating mechanism comprising a casing forming a pressure chamber, a piston operable in said chamber, means for generating pressure for actuating said piston including a plurality of normally stationary explosive charges in said chamher, a source of electric potential, a circuit controlling device operatively connected to said piston for connecting a fresh charge to said potential in response to actuation of said piston, and a control switch for completing the firing circuit 01' said charge.

2. Operating mechanism comprising a casing forming a pressure chamber, a piston operable in said chamber, a plurality of normally stationary explosive charges in said chamber, a source of 1 electric potential, a circuit controlling device having a plurality of contacts individually connected to said charges, means including a pawl and ratchet operatively connected to said piston for successively connecting said potential to each of said 1 charges, and a control switch for completing the charge firing circuit.

3. In a circuit breaker closing system including a circuit breaker having a force-transmitting 5 ,linkage, means for actuating said linkage comprising a casing forming a pressure chamber, a piston operable in said chamber and adapted to engage said linkage, means for generating pressure for actuating said piston including a plurality 10 of stationary explosive charges, a circuit control- 15 circuit of said charge.

4. In a circuit breaker closing system includin a circuit breaker having a force-transmitting linkage, means for actuating said linkage comprising a casing forming a pressure chamber, a piston operable in said chamber and adapted to engage said linkage, means for generating pressure for actuating said piston including a plurality of explosive charges, an auxiliary switch operatively connected to said linkage, a circuit controller in series with said auxiliary switch operatively connected to said piston for establishing a firing connection with a fresh charge in response to a circuit closing operation, and means for completing the firing circuit of said charge.

DAVID C. PRINCE. 

